hdu1200

/**/
#include <cstdio>
#include <cstring>
#include <cmath>
#include <cctype>
#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <vector>
#include <string>
#include <stack>
#include <queue>

typedef long long LL;
using namespace std;

int n;
char s[205], str[25][205];

int main()
{
	//freopen("in.txt", "r", stdin);
	//freopen("out.txt", "w", stdout);

	while(scanf("%d", &n) == 1){
		if(!n) break;
		int len, cnt = 0;
		scanf("%s", s);
		len = strlen(s);
		for (int i = 1; i <= len / n; i++){
			if(i & 1){
				for(int j = 1; j <= n; j++){
					str[i][j] = s[cnt++];
				}
			}else{
				for (int j = n; j >= 1; j--){
					str[i][j] = s[cnt++];
				}
			}
		}
		for (int i = 1; i <= n; i++){
			for (int j = 1; j <= len / n; j++){
				printf("%c", str[j][i]);
			}
		}
		printf("\n");
	}

	return 0;
}
/**/